nfnetlink_log: do not expose NFULNL_COPY_DISABLED to user-space

This patch moves NFULNL_COPY_PACKET definition from
linux/netfilter/nfnetlink_log.h to net/netfilter/nfnetlink_log.h
since this copy mode is only for internal use.

I have also changed the value from 0x03 to 0xff. Thus, we avoid
a gap from user-space that may confuse users if we add new
copy modes in the future.

This change was introduced in:
http://www.spinics.net/lists/netfilter-devel/msg13535.html



Since this change is not included in any stable Linux kernel,
I think it's safe to make this change now. Anyway, this copy
mode does not make any sense from user-space, so this patch
should not break any existing setup.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>